Bottles utilized for chemical purpose are required to be thoroughly washed and rinsed before their use for the purpose of preventing contamination caused by impurities. The washing of narrow neck bottles is done by washing the interior of the bottle with a brush and a detergent, and then rinsing with clean water for several times. However, in a narrow neck bottle, discharge of the water poured therein is not easy because of its narrow neck, so that much time and labor are required before the interior of the bottle becomes clean enough, without any residue of the detergent. This requires substantial rinsing.
However, since washing the outer surface of the bottle is relatively easy, a method of readily washing the interior of the bottle has been proposed. More particularly, the washing of the outer surface of the bottle can readily be performed by causing the water to flow down along the outer surface. Such washing is easier than the washing of the interior. The proposed method of washing the interior is based on the same phenomenon, that is to cause the water to flow down along the inside surface of the bottle.
According to this method, a tube is inserted into the neck of an inverted bottle, and water is injected upon the bottom surface of the interior of the bottle through the tube. However, the bottle to be rinsed is in a state immediately after washing with a brush and detergent such that the interior of the bottle is filled with the foam resulting from this method. Even though the water flows down along the inner surface of the bottle in the form of a thin film, the foam can not be removed readily, thus failing to rapidly and readily rinse the bottom of the bottle.
This is caused by the fact that although the water poured into the bottle flows along the inner surface in the form of a thin film, the water flows out without entrapping the foam therein, and residual water remains in the bottle so that at the time of injecting the rinsing water, the air in the bottle is entrapped in the rinsing water, thereby forming new foam with the detergent.